As North Atlantic right whale calving season ends, New England Aquarium scientists are sounding the alarm that the number of mother-calf pairs documented this season is far below what’s needed to sustain the critically endangered species.
The annual calving season in the southeastern U.S. produced 11 mother-calf pairs and a 12th calf without an observed mother. Nine of those calves were born by the end of December, with the last one detected on Jan. 20.
In the last 10 years, scientists have documented 108 calves born, while the previous 10 years yielded 216 calves.
“There were half as many right whales born this past decade,” said senior scientist Philip Hamilton, who leads the New England Aquarium’s right whale research program in the Anderson Cabot Center for Ocean Life.
“To reach the previous decade’s number, we would need an average of 22 right whales born each year,” Hamilton added. “It is certainly concerning for a population that has experienced a sharp decline in recent years.”
The current North Atlantic right whale population is estimated at less than 350 individuals, representing an ongoing downward trend for the species amid concerns that human impacts are affecting the animals’ ability to survive and reproduce.
Until recently, right whales began calving by age 10, but now most are not doing so — nearly 50 female whales over the age of 10 who were seen in recent years have not calved. “Pilgrim” ended up being the only new mom of this calving season, surprising researchers by breaking this new pattern and giving birth to her first calf at 10-years-old.
Ten of the 11 mothers have already been seen in Massachusetts waters this spring by scientists from the Center for Coastal Studies and other research groups. “Porcia” and her calf were sighted in Cape Cod Bay on March 18, an early arrival to the area that could be a sign of shifts in the timing of right whales’ northward migration amid warming ocean temperatures.
As right whales shift their habitat use as a result of climate change and availability of food resources, the animals are at greater risk of both vessel strikes and entanglements in fishing gear along the East Coast of the U.S. and Canada.
“So far, the only mother from the calving season not spotted in Cape Cod Bay is ‘Archipelago,’ which is not a big surprise since she didn’t bring either of her previous calves to these waters,” Hamilton said. “We have found that some mothers feed elsewhere, though we don’t always know where. That’s why ongoing research and monitoring is so critical to both understanding and protecting this species.”